Most homeowners pay little attention to how their toilets work until something goes wrong or they’re in the market for a bathroom update. When it’s time to replace this under appreciated bathroom fixture, you’ll likely notice that there are options far beyond the old-school porcelain thrones.

Modern toilet flush systems have advanced technologies that reduce water usage, help keep the bowl clean, have different dimensions and provide more powerful suction. So, which should you choose to meet your family’s needs?

Quick Overview On How Toilets Work

Since the dawn of humankind, people have created systems to eliminate waste. It wasn’t until 1775 that we saw the first modern gravity-flush toilet, thanks to a Scottish watchmaker named Alexander Cummings

His original design consisted of a pan of water connected to an S-bend waste pipe that prevented odors and bacteria from traveling back into the home. When bathroom visitors pulled a cord, it released the flush valve over the waste pipe. Gravity pushed the bowl contents downwards and through the septic system. 

Modern toilets still have these same essential components: a toilet tank to store water, a bowl to hold waste, and a valve that keeps water inside the tank until it’s time to flush. 

Pushing the handle or button on the toilet tank lifts the flapper valve between the tank and the bowl. Stored water enters the bowl through the rim holes as the tank empties, allowing the valve to fall back into place and the fill float to drop. The sinking float opens the fill valve, queuing up water in the tank for the next flush. 

Meanwhile, gravity forces the water and waste in the bowl through the hole in the bottom. It overflows the trapway, creating a siphon that sucks everything out of the bowl. Air rushes into the trapway, filling the space where the water was and cutting off the suction. 

Finally, as the water supply line fills the tank, some water moves into the bowl via the refill tube. Once the tank is full and the float lifts back into its original position, the water supply line shuts off, and the toilet is ready to use again. 

1. Gravity Flush Systems

Gravity flush toilets are one of the most popular types, as they don’t require mechanical assistance to release the water from the bowl. As the name implies, they rely on gravitational force, using the weight of the water inside the tank to push waste down the toilet trap.

When you push the handle on a gravity flush system, it lifts the flush lever inside of the tank. Gravity sends the water downwards into the bowl via rim holes. As the water flows downward, it pushes waste into the trapway and through the S-bend pipes. 

As the wastewater overflows the trapway, it activates a natural vacuum within the pipes. Water forces the air trapped inside the lines downwards, creating suction. When the wastewater is gone, air rushes back in to cut off the siphon. 

Gravity flush systems are often the least expensive option, though they use a lot of water to complete the flushing phase. 

2. Pressure-Assisted Flushing System

Pressure-assisted flushing systems work in much the same way as a gravity flush system, but they have the increased force of pressurized air to help clear the contents of the bowl. 

In addition to the tank filling and valve system, these toilets include an airtight tank inside the porcelain tank. It works by trapping air inside to build up pressure. This air pressure puts much more force behind the water upon flushing, sending it through the rim holes at explosive speeds. 

One of the key benefits of a pressure-assisted flushing system is that it uses much less water than gravity flush systems. The high-velocity water helps break up waste as it’s propelled down the bowl, which means that the trapway doesn’t need as much pressure to overflow and send the waste down into the pipes. 

Not only does this help prevent clogs, but it also keeps the bowl cleaner. At such high speeds, the tank water effectively scrubs debris away, leaving little waste behind. However, the water pressure explosion makes for a particularly loud flush. 

Read More: How To Remove Hard Water Stains From A Toilet

3. Dual Flush System

Another popular option for reducing water consumption is the dual flush system. It allows users to customize the volume of water that exits the tank according to the type of waste– A half-flush for liquid or a full flush for solid. 

Rather than relying on siphon tube suction, dual flush toilets have much larger trapways, which means that waste can exit the bowl without large volumes of water. They also employ a washdown method, dumping the proper amount of the tank all at once to force the waste out. 

Most dual flush systems utilize a two-sided button and tower fill valve to control the tank release. Owners push the left side to get rid of liquid waste and the right to get rid of solid. Others have a handle that you can raise or lower depending on the type of waste. 

Compared to single flush systems, dual flush toilets keep less water in the bowl, so they tend to require more cleaning than other options. 

4. Single Flush System

Most home toilets are single flush systems. They dump the entire water tank with every flush, a major contributing factor to the EPA’s estimate that toilets account for 30% of home water usage. 

Single flush toilets require large volumes of water to create enough gravitational force to push wastewater over the trapway and through the S-bend pipes. That’s why flushing won’t work if the tank isn’t filled. The water’s weight isn’t enough to contend with the waste and form the necessary vacuum in the trapway.  

They tend to be easier for the layman to repair as it’s easy to find parts, and the mechanisms are simpler. They are also less expensive to maintain over time because you won’t have to search for a specialty plumber for more serious issues. 

That said, they’re not ideal for lowering your water bill.  Single flush systems require more water in the bowl to siphon waste effectively through the trapway. This increased volume helps keep the bowl cleaner than dual flush systems in exchange for increased water consumption. 

Read More: How To Remove Ring Around Toilet

5. Siphon Flush System 

Siphon flush toilets are synonymous with gravity flush toilets. It simply means that suction assists waste over and through the trapway. As water runs from the tank into the bowl, a specific hole in the rim called the siphon jet-hole directs it into the trapway to start the siphoning process.

When your toilet isn’t in use, the septic pipes are full of air. The water running through the siphon jet-hole pushes directly against the air, creating downward pressure within the S-bend pipes. This forced air forms a vacuum that sucks the contents of the bowl into your septic pipes. 

Siphon flush system toilets must have smaller trapway holes to form the necessary suction, which means that they sometimes require multiple flushes to get rid of all waste. 

Like single flush systems, though, the higher in-bowl water levels keep toilets much cleaner. 

6. Double Cyclone Flush System

Double Cyclone flush system toilets are a flushing method invented by Toto, which owns the rights to the patent and name. It relies on centrifugal force created by water nozzles to circulate the tank water around the bowl before it enters the trapway. 

When you flush a Double Cyclone toilet, gravity pushes water into a primary and secondary nozzle. These nozzles are pointed in the same direction, creating the same motion we see in tornadoes. The spinning “waterspout” travels around the bowl rather than going straight down into the trapway. 

As the water spins, it also gains velocity, making for a stronger flush despite using less water than a traditional toilet. 

Double Cyclone flush toilets are rimless, so you won’t have to worry about unseen debris getting trapped in your bowl. The rimless design and the 360-degree water motion make cleanup an effortless endeavor. 

One disadvantage of the Double Cyclone flush toilet is that parts can be more challenging to replace, and you may require a specialty plumber to handle the job. These factors increase the overall cost of maintenance.

7. Tornado Flush System

The Tornado flush system is another innovation from Toto. It works very similarly to the Double Cyclone toilets but incorporates the dual flushing mechanism to reduce water consumption further. 

Tornado flush toilets form the same cyclonic water action inside the bowl, spinning around the entire interior to build up velocity for a stronger flush. At the same time, it rinses away any wayward waste, keeping the interior sparkling clean. 

The critical difference of the Tornado system is its dual flushing capabilities. The tank has a button on top that lets you control the amount of water released. It uses less water to eliminate liquid waste but increases the flush volume to push solid waste through the trapway. 

8. Ballcock Flush System

The fill valves on gravity flush toilets rely on a ballcock component to control the water supply line. At its most basic, it consists of a floating, hollow “ball” made of either plastic or brass attached to a lift arm. The lift arm controls the water supply fill valve.  

When the toilet is not in use, the ballcock floats on top of the water in the tank. As soon as the toilet flushes and the water level drops, the ballcock falls and raises the lift arm connected to the fill valve. The fill valve then opens the water supply line, refilling the tank. 

As the water levels rise, the ballcock raises back up and disengages the valve, turning the water supply off once it’s reached the proper level. 

Depending on the model and brand of toilet you own, the specs and manuals may refer to this piece as a balltap or float valve.  

9. Tower Style Flush System

Dual-flush toilets rely on a tower style flush system to control the amount of water released from the bowl. 

Unlike traditional, flat rubber flappers, which empty the entire tank when lifted, tower flush valves can wholly or partially lift depending on which flush button you press. They are shaped like cylindrical towers with a rubber gasket on the bottom that keeps water in the tank until the toilet flushes. 

When you press the liquid waste button, the tower mechanism lifts only partway, releasing around half of the tank’s contents into the bowl. Engaging the solid waste button lifts the tower completely, allowing for a more powerful flush, thanks to the additional water pressure.

Toilets equipped with tower flush valves have increased flushing power due to the wider diameter of the hole between the tank and the bowl. This uptick in size increases the water’s force, sending it spinning around the bowl. 

The only actual downside to tower flush valves is the increased maintenance requirements. Similarly to standard flappers, the rubber gasket in tower style flush systems may need replacing due to wear and tear. 

While this process is simple, repairing more complicated components like the button mechanisms can be tricky compared to flappers. 

10. Double Vortex Flush System

The Double Vortex flush system is one of the most recent updates to toilet technology. Rather than sending water down through the flush valve, American Standard’s Double Vortex flush systems release all the water in the tank through two sideways openings inside the bowl. 

As the water moves into the rim chamber, pressurized air forces it out into the bowl, creating the vortex effect. From there, the water and bowl contents move to the bowl jet, activating the siphon action to suck the waste out. 

These toilets are particularly popular for those who dread the task of scrubbing their toilet because they keep the inside of the bowl clean. Despite using much less water than more conventional systems, the increased force of the water circulating the rimless bowl is highly effective at removing waste. 

Frequently Asked Questions

  • What type of toilet flush system is best?

    There is no “best” type of toilet flush system. Homeowners should choose whichever kind best fits their needs. Gravity flush systems are typically less expensive, quieter, and easier to repair, but they aren’t as effective in high-usage settings– like retail stores– or very large households.

  • Can you replace the flushing mechanism in a toilet?

    You can replace the flushing mechanism in a toilet without replacing the entire fixture. It typically requires removing the whole tank from the bowl, so many homeowners prefer to let their plumber handle the job.

  • Can you make your toilet flush stronger?

    You can make your toilet flush stronger by increasing the water pressure. Sometimes it’s as simple as cleaning the rim holes or replacing the fill valve.

    In some cases, the only way to increase water pressure is by raising the tank to put a more potent gravitational force behind the flush.

  • Do some toilets flush better than others?

    Pressure-assisted flush system toilets tend to flush better as they benefit from high-velocity, pressurized air to send waste into the trapway.

Final Thoughts

Not all toilet flush systems are the right choice for every home. While all methods have pros and cons, you should base your decision on the size of your household, water consumption concerns, and how often you’re willing to pick up the toilet brush. 

The right toilet choice can change your life or, at the very least, make using your restroom a more pleasant experience.